scholarly journals Study on the Formation of Reactive Material Shaped Charge Jet by Trans-Scale Discretization Method

Crystals ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 107
Author(s):  
Guancheng Lu ◽  
Chao Ge ◽  
Zhenyang Liu ◽  
Le Tang ◽  
Haifu Wang
Keyword(s):  
Formation Process ◽  
High Speed ◽  
Element Model ◽  
Particle Dispersion ◽  
Shaped Charge ◽  
Size Difference ◽  
Discretization Method ◽  
Particle Content ◽  
Bottom Part ◽  
Reactive Material

The formation process of reactive materials shaped charge is investigated by X-ray photographs and numerical simulation. In order to study the formation process, a trans-scale discretization method is proposed. A two-dimensional finite element model of shaped charge and reactive material liner is established and the jet formation process, granule size difference induced particle dispersion and granule distribution induced jet particle distribution are analyzed based on Autodyn-2D platform and Euler solver. The result shows that, under shock loading of shaped charge, the Al particle content decreases from the end to the tip of the jet, and increases as the particle size decreases. Besides, the quantity of Al particles at the bottom part of the liner has more prominent influence on the jet head density than that in the other parts, and the Al particle content in the high-speed section of jet shows inversely proportional relationship to the ratio of the particle quantity in the top area to that in the bottom area of liner.

scholarly journals Research on the Ignition Height and Reaction Flame Temperature of PTFE/Al/Si/CuO with Different Mass Ratios of PTFE/Si

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3464
Author(s):  
Xuan Zou ◽  
Jingyuan Zhou ◽  
Xianwen Ran ◽  
Yiting Wu ◽  
Ping Liu ◽  
...  
Keyword(s):  
Energy Release ◽  
High Speed ◽  
Flame Temperature ◽  
Sintering Process ◽  
Release Process ◽  
Reactive Material ◽  
Temperature Changes ◽  
Release Capacity ◽  
Mass Ratios ◽  
The Relationship

Recent studies have shown that the energy release capacity of Polytetrafluoroethylene (PTFE)/Al with Si, and CuO, respectively, is higher than that of PTFE/Al. PTFE/Al/Si/CuO reactive materials with four proportions of PTFE/Si were designed by the molding–sintering process to study the influence of different PTFE/Si mass ratios on energy release. A drop hammer was selected for igniting the specimens, and the high-speed camera and spectrometer systems were used to record the energy release process and the flame spectrum, respectively. The ignition height of the reactive material was obtained by fitting the relationship between the flame duration and the drop height. It was found that the ignition height of PTFE/Al/Si/CuO containing 20% PTFE/Si is 48.27 cm, which is the lowest compared to the ignition height of other Si/PTFE ratios of PTFE/Al/Si/CuO; the flame temperature was calculated from the flame spectrum. It was found that flame temperature changes little for the same reactive material at different drop heights. Compared with the flame temperature of PTFE/Al/Si/CuO with four mass ratios, it was found that the flame temperature of PTFE/Al/Si/CuO with 20% PTFE/Si is the highest, which is 2589 K. The results show that PTFE/Al/Si/CuO containing 20% PTFE/Si is easier to be ignited and has a stronger temperature destruction effect.

Simulation and Experiment on the Residual Stress in Super-High Speed Grinding

2010 ◽  
Vol 135 ◽  
pp. 238-242
Author(s):  
Yue Ming Liu ◽  
Ya Dong Gong ◽  
Wei Ding ◽  
Ting Chao Han
Keyword(s):  
Residual Stress ◽  
High Speed ◽  
Element Model ◽  
Residual Stress Distribution ◽  
X Ray Diffraction ◽  
Machined Surface ◽  
X Ray ◽  
High Speed Grinding ◽  
Simulation And Experiment ◽  
Cylindrical Workpiece

In this paper, effective finite element model have been developed to simulation the plastic deformation cutting in the process for a single particle via the software of ABAQUS, observing the residual stress distribution in the machined surface, the experiment of grinding cylindrical workpiece has been brought in the test of super-high speed grinding, researching the residual stress under the machined surface by the method of X-ray diffraction, which can explore the different stresses from different super-high speed in actual, and help to analyze the means of reducing the residual stresses in theory.

Durability Analysis of the Reduction Gear for High Speed Train Considering Driving Histories

2012 ◽  
Vol 586 ◽  
pp. 269-273
Author(s):  
Chul Su Kim ◽  
Gil Hyun Kang
Keyword(s):  
Fatigue Life ◽  
High Speed ◽  
Element Model ◽  
Rolling Stock ◽  
Reduction Gear ◽  
High Speed Train ◽  
Analysis Software ◽  
Tractive Effort ◽  
Durability Analysis ◽  
The Finite Element Model

To assure the safety of the power bogies for train, it is important to perform the durability analysis of reduction gear considering a variation of velocity and traction motor capability. In this study, two types of applied load histories were constructed from driving histories considering the tractive effort and the train running curves by using dynamic analysis software (MSC.ADAMS). Moreover, this study was performed by evaluating fatigue damage of the reduction gears for rolling stock using durability analysis software (MSC.FATIGUE). The finite element model for evaluating the carburizing effect on the gear surface was used for predicting the fatigue life of the gears. The results showed that the fatigue life of the reduction gear would decrease with an increasing numbers of stops at station.

scholarly journals Deformation Law and Control Limit of CRTSIII Slab Track under Subgrade Frost Heave

2021 ◽  
Vol 11 (8) ◽  
pp. 3520
Author(s):  
Xiaopei Cai ◽  
Qian Zhang ◽  
Yanrong Zhang ◽  
Qihao Wang ◽  
Bicheng Luo ◽  
...  
Keyword(s):  
High Speed ◽  
Base Plate ◽  
Element Model ◽  
Middle Part ◽  
Railway Track ◽  
Frost Heave ◽  
Track Structure ◽  
Slab Track ◽  
Plastic Damage ◽  
Track Irregularity

In order to find out the influence of subgrade frost heave on the deformation of track structure and track irregularity of high-speed railways, a nonlinear damage finite element model for China Railway Track System III (CRTSIII) slab track subgrade was established based on the constitutive theory of concrete plastic damage. The analysis of track structure deformation under different subgrade frost heave conditions was focused on, and amplitude the limit of subgrade frost heave was put forward according to the characteristics of interlayer seams. This work is expected to provide guidance for design and construction. Subgrade frost heave was found to cause cosine-type irregularities of rails and the interlayer seams in the track structure, and the displacement in lower foundation mapping to rail surfaces increased. When frost heave occured in the middle part of the track slab, it caused the greatest amount of track irregularity, resulting in a longer and higher seam. Along with the increase in frost heave amplitude, the length of the seam increased linearly whilst its height increased nonlinearly. When the frost heave amplitude reached 35 mm, cracks appeared along the transverse direction of the upper concrete surface on the base plate due to plastic damage; consequently, the base plate started to bend, which reduced interlayer seams. Based on the critical value of track structures’ interlayer seams under different frost heave conditions, four control limits of subgrade frost heave at different levels of frost heave amplitude/wavelength were obtained.

Wear Behavior of In Situ Mg2Si Particle-Dispersed Magnesium Alloys

2017 ◽  
Vol 909 ◽  
pp. 100-105
Author(s):  
Kazunori Asano
Keyword(s):  
Magnesium Alloys ◽  
High Speed ◽  
Wear Behavior ◽  
Particle Dispersion ◽  
Dry Sliding Wear ◽  
Wear Loss ◽  
Mg2si Particle ◽  
Particle Volume ◽  
Volume Fractions

Magnesium alloys, in which the in-situ Mg2Si particles were dispersed, were fabricated by a casting process, and the dry sliding wear behavior of the alloys was investigated. Optical microscopy revealed that the polygonal Mg2Si particles were homogeneously dispersed in the alloys. Mg2Si particle volume fractions in the alloys were 7 and 11 vol%. Although the wear loss of the alloy decreased due to the particle-dispersion, there was no difference in the wear loss between the alloys with different volume fractions. The worn surfaces of the particle-dispersed alloys were covered with the crumbled Mg2Si particles, which would prevent seizure between the alloy and the steel counterpart, leading to an improvement in the wear resistance of the alloy. The particle-dispersion slightly decreased the scatter of the coefficient of friction during the wear for the low sliding speed and load, but the effect of the dispersion was not clearly observed for the high speed and load.

Research on the Effects of Welding Sequence on Welding Residual Stress of High-Speed Train Based on SYSWELD

2011 ◽  
Vol 399-401 ◽  
pp. 1806-1811
Author(s):  
Yong Hong Chen ◽  
Peng Chen ◽  
Ai Qin Tian
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
High Speed ◽  
Element Model ◽  
Welding Residual Stress ◽  
High Speed Train ◽  
Distribution Law ◽  
Element Analysis ◽  
Welding Sequence ◽  
Maximum Residual Stress

The finite element model of the roof of aluminum high-speed train was established, double ellipsoid heat source was employed, and heat elastic-plastic theory was used to simulate welding residual stress of the component under different welding sequence based on the finite element analysis software SYSWELD. The distribution law of welding residual stress was obtained. And the effects of the welding sequence on the value and distribution of residual stress was analyzed. The numerical results showed that the simulation data agree well with experimental test data. The maximum residual stress appears in the weld seam and nearby. The residual stress value decreases far away from the welding center. Welding sequence has a significant impact on the final welding residual stress when welding the roof of aluminum body. The side whose residual stress needs to be controlled should be welded first.

Thermal Characters of the Air-Cooled High Speed Motorized Spindle for Wood-Working Machine

2013 ◽  
Vol 579-580 ◽  
pp. 568-572
Author(s):  
Da Guo Ma ◽  
Xin Bo Jiang
Keyword(s):  
High Speed ◽  
Metal Cutting ◽  
Heat Dissipation ◽  
Element Model ◽  
Structure Design ◽  
Air Cooling ◽  
Heat Sources ◽  
Motorized Spindle ◽  
Dissipation Structure ◽  
Motorized Spindles

The structure and composition of the air-cooled high speed motorized spindle for wood-working machine and some features relative to the metal cutting motorized spindle are introduced briefly. Then the main heat sources and heat dissipation mechanism of the air-cooled motorized spindle are thoroughly analyzed, finite element model of the air-cooled motorized spindle is built, the motorized spindles temperature distribution under thermal steady state and the influence of speed are analyzed. The results show that air cooling relative to the water or oil cooling has many advantages and reasonable heat dissipation structure design of air-cooled motorized spindle could meet the requirements of the high-speed motorized spindle for wood-working machine.

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